smp_call_function_single(): be slightly less stupid
If you do
smp_call_function_single(expression-with-side-effects, ...)
then expression-with-side-effects never gets evaluated on UP builds.
As always, implementing it in C is the correct thing to do.
While we're there, uninline it for size and possible header dependency
reasons.
And create a new kernel/up.c, as a place in which to put
uniprocessor-specific code and storage. It should mirror kernel/smp.c.
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/include/linux/smp.h b/include/linux/smp.h
index b824669..715196b 100644
--- a/include/linux/smp.h
+++ b/include/linux/smp.h
@@ -24,6 +24,9 @@
/* total number of cpus in this system (may exceed NR_CPUS) */
extern unsigned int total_cpus;
+int smp_call_function_single(int cpuid, void (*func) (void *info), void *info,
+ int wait);
+
#ifdef CONFIG_SMP
#include <linux/preempt.h>
@@ -79,8 +82,6 @@
return 0;
}
-int smp_call_function_single(int cpuid, void (*func) (void *info), void *info,
- int wait);
void __smp_call_function_single(int cpuid, struct call_single_data *data);
/*
@@ -140,14 +141,6 @@
static inline void smp_send_reschedule(int cpu) { }
#define num_booting_cpus() 1
#define smp_prepare_boot_cpu() do {} while (0)
-#define smp_call_function_single(cpuid, func, info, wait) \
-({ \
- WARN_ON(cpuid != 0); \
- local_irq_disable(); \
- (func)(info); \
- local_irq_enable(); \
- 0; \
-})
#define smp_call_function_mask(mask, func, info, wait) \
(up_smp_call_function(func, info))
#define smp_call_function_many(mask, func, info, wait) \
diff --git a/kernel/Makefile b/kernel/Makefile
index 2921d90..2aebc4c 100644
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -40,7 +40,11 @@
obj-$(CONFIG_DEBUG_RT_MUTEXES) += rtmutex-debug.o
obj-$(CONFIG_RT_MUTEX_TESTER) += rtmutex-tester.o
obj-$(CONFIG_GENERIC_ISA_DMA) += dma.o
-obj-$(CONFIG_USE_GENERIC_SMP_HELPERS) += smp.o
+ifeq ($(CONFIG_USE_GENERIC_SMP_HELPERS),y)
+obj-y += smp.o
+else
+obj-y += up.o
+endif
obj-$(CONFIG_SMP) += spinlock.o
obj-$(CONFIG_DEBUG_SPINLOCK) += spinlock.o
obj-$(CONFIG_PROVE_LOCKING) += spinlock.o
diff --git a/kernel/up.c b/kernel/up.c
new file mode 100644
index 0000000..ce62cc9
--- /dev/null
+++ b/kernel/up.c
@@ -0,0 +1,18 @@
+/*
+ * Uniprocessor-only support functions. The counterpart to kernel/smp.c
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/smp.h>
+
+int smp_call_function_single(int cpu, void (*func) (void *info), void *info,
+ int wait)
+{
+ WARN_ON(cpuid != 0);
+ local_irq_disable();
+ (func)(info);
+ local_irq_enable();
+ return 0;
+}
+EXPORT_SYMBOL(smp_call_function_single);